Which of the following is the preferred biomarker for the assessment of myocardial necrosis?

• A. CK
• B. AST
• C. CK-MB
• D. TnI

Answer: (D)

Troponin I is the preferred biomarker for myocardial necrosis because it is highly specific to cardiac muscle and is released into the bloodstream when heart muscle cells are damaged. It rises promptly after injury and stays elevated for an extended period, which provides a reliable window for detecting myocardial infarction with high diagnostic accuracy. Enzymes like CK and its MB fraction can be elevated for other reasons, such as skeletal muscle injury, making them less specific. AST is even less specific, since it is present in liver and other tissues. With modern high-sensitivity troponin assays, troponin I offers the best combination of specificity and sensitivity for identifying myocardial necrosis.